Human Sensorimotor Control Laboratory, University of Minnesota, Minneapolis, Minnesota, USA; Center for Clinical Movement Science, University of Minnesota, Minneapolis, Minnesota, USA.
Mov Disord. 2014 Feb;29(2):221-8. doi: 10.1002/mds.25731. Epub 2013 Nov 15.
An established treatment for the motor symptoms of Parkinson's disease (PD) is deep brain stimulation (DBS) of the subthalamic nucleus (STN). Mounting evidence suggests that PD is also associated with somatosensory deficits, yet the effect of STN-DBS on somatosensory processing is largely unknown. This study investigated whether STN-DBS affects somatosensory processing, specifically the processing of tactile and proprioceptive cues, by systematically examining the accuracy of haptic perception of object size. (Haptic perception refers to one's ability to extract object features such as shape and size by active touch.) Without vision, 13 PD patients with implanted STN-DBS and 13 healthy controls haptically explored the heights of 2 successively presented 3-dimensional (3D) blocks using a precision grip. Participants verbally indicated which block was taller and then used their nonprobing hand to motorically match the perceived size of the comparison block. Patients were tested during ON and OFF stimulation, following a 12-hour medication washout period. First, when compared to controls, the PD group's haptic discrimination threshold during OFF stimulation was elevated by 192% and mean hand aperture error was increased by 105%. Second, DBS lowered the haptic discrimination threshold by 26% and aperture error decreased by 20%. Third, during DBS ON, probing with the motorically more affected hand decreased haptic precision compared to probing with the less affected hand. This study offers the first evidence that STN-DBS improves haptic precision, further indicating that somatosensory function is improved by STN-DBS. We conclude that DBS-related improvements are not explained by improvements in motor function alone, but rather by enhanced somatosensory processing.
一种治疗帕金森病（PD）运动症状的成熟疗法是丘脑底核（STN）的深部脑刺激（DBS）。越来越多的证据表明，PD 还与躯体感觉缺陷有关，但 STN-DBS 对躯体感觉处理的影响在很大程度上尚不清楚。本研究通过系统检查触觉感知物体大小的准确性，研究了 STN-DBS 是否会影响躯体感觉处理，特别是触觉和本体感觉线索的处理。在没有视觉的情况下，13 名植入 STN-DBS 的 PD 患者和 13 名健康对照者使用精密抓握主动触摸的方式触觉探索连续呈现的 2 个 3 维（3D）块的高度。参与者口头指示哪个块更高，然后用非探测手电机匹配比较块的感知大小。患者在药物洗脱 12 小时后进行 ON 和 OFF 刺激测试。首先，与对照组相比，PD 组在 OFF 刺激下的触觉分辨阈值升高了 192%，平均手开口误差增加了 105%。其次，DBS 将触觉分辨阈值降低了 26%，开口误差降低了 20%。第三，在 DBS ON 期间，与运动功能受影响较小的手相比，用受影响较大的手进行探测会降低触觉精度。本研究首次提供了 STN-DBS 可提高触觉精度的证据，进一步表明 STN-DBS 可改善躯体感觉功能。我们得出结论，DBS 相关的改善不能仅用运动功能的改善来解释，而是通过增强躯体感觉处理来实现。
